1. Field of the Invention
This invention relates to a system for control of electrical power consumption. More particularly, this invention relates to a method and apparatus for control and regulation of electrical power and reduction of energy consumption of a load such as lights and motors.
2. The Prior Art
A variety of AC power regulating circuits are known in the art in which AC power to a load (e.g., fluorescent lamps, motors, etc.) is regulated. For example, a proper circuit can be used to dim lights by reducing amperage used by the lights, which reduces the power consumed and saves energy.
One type of prior art uses an autotransformer for changing the voltage on the load. In one application, the primary winding of the autotransfomer has some parallel shunt resistors and proper combination of switches to allow that the power supplied to the load is discretely changed. One problem related to this application is that the load is subjected to a series of stresses, which can cause damage to the load. In another application, autotransfomers with moving wiper contact arrangement are utilized. However, in the prior art, autotransfomers are often directly coupled to the load, which subjects autotransfomers to constant stresses.
Another type prior art uses relays in conjunction with an autotransformer for changing the voltage on the load. PCT Publication WO 98/53648 by Reverberi discloses a centralized power reducing device using an autotransformer and means of relays controlled by a logic unit.
Additionally, a common problem associated with the prior art is lacking of flexibility for a user to regulate power consumption according to location of the load and changing demand with time. For example, lighting demand in office area depends on whether it is a working day (normally Monday to Friday) or an off day (weekends and holidays). For any given day, the demand also depends on whether it is open hours or closed hours (e.g., night).
Thus, there is still a need for a new and improved power regulation system for better performance.
The above-noted disadvantages of the prior art are overcome by the present invention, which in one aspect is a power regulation system coupled to an AC power source outputting an input voltage between a first node and a second node. In a single phase system, the first node can be connected to a power path, and the second node can be connected to neutral or ground. Included in the system is a first transformer having a winding having a first end and a second end, wherein the first end is electrically coupled to the first node and the second end is electrically coupled to the second node to receive the input voltage, and a movable wiper arm having a wiper, an output node and a body therebetween, wherein the movable wiper arm is movable continuously between the second end and the first end of the winding so that a control voltage is generated between the output node and the second end within a range of from 0 volts to at least the input voltage. The system also has a second transformer that has a primary coil having a first end and a second end, wherein the first end is electrically coupled to the output node and the second end is electrically coupled to the second node to receive the control voltage from the first transformer, and a secondary coil having a first end and a second end, wherein the first end is electrically coupled to the first node. The system can be used in connection with a load having a first terminal and a second terminal can also be included in the system, wherein the first terminal is electrically connected to the second end of the second transformer and the second terminal is electrically coupled to the second node.
In one embodiment of the present invention, the primary coil and secondary coil are electromagnetically coupled to each other and so arranged that when the control voltage from the first transformer is applied to the first end and the second end of the primary coil, an output voltage is generated between the first end and the second end of the secondary coil, wherein the output voltage is substantially 180xc2x0 out of phase from the input voltage so as to generate an effective voltage applied to the load, and wherein the effective voltage is less than the input voltage and substantially equals to the difference between the input voltage and the output voltage, resulting a reduction in power consumption of the load.
In another embodiment of the present invention, the system further includes a driver engaging the movable wiper arm through the body of the movable wiper arm, and a controller, in control communication with the driver, that causes the driver to move the movable wiper arm to a selected position between the second end and the first end of the winding, so that a control voltage with a selected value is generated between the output node and the second end of the winding.
In another aspect, the invention includes a power regulation system coupled to an AC power source being a three-phase or multi-phase system, each phase outputting an input voltage related to neutral, respectively. On each phase of the AC power source, the system includes a first transformer having a winding having a first end and a second end electrically coupled to the phase and neutral, respectively to receive the input voltage from the phase, and a movable wiper arm having a wiper, an output node and a body therebetween, wherein the movable wiper arm is movable continuously between the second end and the first end of the winding so that a control voltage is generated between the output node and the second end within a range of from 0 volts to at least the input voltage. The system also includes, on each phase, a second transformer having a primary coil having a first end and a second end, wherein the first end is electrically coupled to the output node and the second end is electrically coupled to neutral to receive the control voltage from the first transformer, and a secondary coil having a first end and a second end, wherein the first end is electrically coupled to the phase. The primary coil and secondary coil are electromagnetically coupled to each other and so arranged that when the control voltage from the first transformer is applied to the first end and the second end of the primary coil, an output voltage is generated between the first end and the second end of the secondary coil, and wherein the output voltage is substantially 180xc2x0 out of phase from the input voltage so as to generate an effective voltage that is less than the input voltage and substantially equals to the difference between the input voltage and the output voltage.
In yet another aspect, the invention includes a power regulation system coupled to an input node for receiving an input voltage and coupled to an output node for outputting an output voltage different from the input voltage. The system has a first power path electrically coupling the input node and the output node to allow a current to flow therethrough. The system also has a power block, a control block and a safety block.
In one embodiment of the invention, the power block is on the first power path and electrically coupled to between the input node and the output node for regulating the current to flow therethrough and establishing the extent of the output voltage at the output node, the power block includes a first transformer electrically coupled in parallel with the first power path, the first transformer having an input node and an output node, and a second transformer electrically coupled in series with the first power path, the second transformer having a primary coil and a secondary coil with reversed polarities. The input node of the first transformer is electrically coupled to the first power path for receiving the input voltage, and the output node of the first transformer is electrically coupled to the primary coil of the second transformer for providing a control voltage to cause the secondary coil of the second transformer to generate an output voltage that can be different from the input voltage.
The control block is electrically coupled to the first power path and in control communication with the power block for providing operating current and setting a control voltage for the power block. The control block has a controller in control communication with the first transformer of the power block for setting the control voltage at a selected voltage.
Moreover, the safety block is electrically coupled to the first power path, the power block and the control block for providing surge protection. The safety block has a transient voltage suppression system electrically connected to the input node and positioned between the input node and the power block, and a shunt contactor electrically coupled between the primary coil of the second transformer of the power block.
Each of the power block, control block and safety block may include one or more additional components.
In yet another aspect, the invention is a method of regulating power to a load in conjunction with a power regulation system having a power path, a first transformer electrically coupled in parallel with the power path, the first transformer having an input node and an output node, and a second transformer electrically coupled in series with the power path, the second transformer having a primary coil and a secondary coil, wherein the input node of the first transformer is electrically coupled to the power path and the output node of the first transformer is electrically coupled to the primary coil of the second transformer. An input voltage is applied through the power path to the input node of the first transformer. A control voltage is then generated at the output node of the first transformer. The control voltage is applied to the primary coil of the second transformer to cause the secondary coil of the second transformer to generate an output voltage that is substantially 180xc2x0 out of phase from the input voltage so as to generate an effective voltage applied to the load, wherein the effective voltage is less than the input voltage, resulting a reduction in power consumption of the load.
In a further aspect, the invention is a computer program product in a computer readable medium of instructions that can utilized in conjunction with a power regulation system. The computer program product includes instructions within the computer readable medium for operating a controller that is in communication with an user interface and a first transformer coupled to a power path for receiving an input voltage at an input node of the first transformer. The computer program product also includes instructions within the computer readable medium for permitting input to the controller by a user to generate a control signal responsive to the input. Additionally, the computer program product includes instructions within the computer readable medium for applying the control signal to the first transformer so that the first transformer generates a control voltage corresponding to the input at an output node of the first transformer, wherein the first transformer is electrically coupled with a second transformer that is coupled to the power path and has a primary coil coupled to the output node of the first transformer and a secondary coil so that when the control voltage is applied to the primary coil of the second transformer, the secondary coil of the second transformer generates an output voltage that is substantially 180xc2x0 out of phase from the input voltage.
These and other aspects will become apparent from the following description of the preferred embodiment taken in conjunction with the following drawings, although variations and modifications may be effected without departing from the spirit and scope of the novel concepts of the disclosure.